Waukegan Harbor has reached a pivotal moment in its history — one that city leaders hope will revive its sagging economy — with the culmination of a 30-year, $150 million cleanup to rid the shoreline of contamination left by the city’s former industrial giants along Lake Michigan.

The U.S. Environmental Protection Agency announced Tuesday that the harbor has met requirements to be removed from a list of 43 polluted sites dubbed the “Great Lakes Areas of Concern.” The federal agency will continue to monitor the site for an unspecified amount of time, possibly a few years, before it is officially “de-listed,” officials said.

Still, the news marks a turning point in the decades-long effort to revitalize the lakefront and downtown Waukegan, a city of about 90,000 people, officials said.

In 1986, then-Mayor Robert Sabonjian announced a redevelopment proposal by promising the city would become “the French Riviera of the Midwest” and said it would resemble wealthy Kenilworth.

That hasn’t happened, but progress has been made, however slow, officials said.

“It is hard to imagine that for decades this magnificent harbor and beautiful stretch of Lake Michigan was viewed as a toxic waste dump,” U.S. Sen. Dick Durbin, said Tuesday, joining Gov. Pat Quinn and U.S. Sen. Mark Kirk at an outdoors news conference with the lake as a backdrop.

“For decades, companies dumped 1 million pounds of PCBs in this harbor,” he said. “This was a dead harbor and dying asset and something needed to be done.”

He noted that the companies that polluted the harbor were deemed responsible for paying only 2 percent of the total cleanup costs.

Over the past year, workers have used hydraulic dredges to scrape at least 124,000 cubic yards of PCB-contaminated “muck” from the harbor, EPA officials said. The sludge now sits within an 8-acre containment cell at a former boat slip, where it will be monitored and eventually covered with fill and grass, officials said.

“It’s like the Fort Knox for PCBs,” said Cameron Davis, an EPA administrator.

PCBs — or polychlorinated biphenyls — are man-made chemicals that have been shown to cause cancer, as well as a variety of other adverse health effects, according to the EPA.

The state of Illinois discovered contamination at the site of the former Outboard Marine Corp. in 1975, the EPA said. Since the early 1990s, the federal agency, the state and responsible parties have worked toward cleaning the harbor and restoring natural dune and swale habitats. The city of Waukegan has since purchased two pieces of land, including the Outboard Marine site, which the EPA cleaned up as a Superfund site.

Local officials have long aspired to redevelop the site; commercial and residential properties, along with a casino farther west, have been among plans discussed. The city is considering the purchase of two more pieces of property, which would give it 1,400 acres to lure developers to the lakefront, Mayor Wayne Motley said.

“Years ago, Waukegan was supposed to be the Riviera of the Midwest,” said Motley, who added that the city has begun working with developers on proposals. “We hope that that does come to pass. We look to build hotels along the lakefront, condominiums and … destination locations.”

State legislators have not approved a casino for Waukegan, but city officials will continue in that quest, Motley said.

Leaders also hope to see the return of fishing, which has been deemed unsafe in prior years because of PCB contamination.

Scraping brown sludge from a small pail, Kirk showed off a bit of the “Waukegan Harbor muck” during the news conference.

“Yeecch,” said Kirk, who has worked for years to obtaining cleanup funding. The “long, lonely battle” began as a grass-roots effort, he said.

At one time, he took a busload of elected Waukegan officials to view the Kenosha lakefront, to demonstrate ways to increase property values with cleanup and redevelopment, Kirk said.

“This was the key to Waukegan’s future,” Kirk said. “It was always an obsession of mine.”

Yet the remaining challenges are as stark as the contrast between Waukegan and many of its Lake County neighbors. The lakefront still bears marks of its industrial past, and the city’s median household income in recent years was slightly more than half that of Lake County as a whole, according to Census data.

Heather Dayenian has fond memories of growing up in Waukegan, and said she is encouraged by recent updates from her friends. Food trucks and bands have helped lure people to the harbor, she said.

“They are trying to bring it back to life,” said Dayenian, 38, of Lindenhurst. “I am excited. I really want the downtown to be like when I was younger. You’d go down to the beach and they’d have a little concession stand on the boardwalk. I’d get Laffy Taffys and ice cream. We would watch fireworks at night.”

But Jim Merlo, who grew up in Waukegan and owns a business there, Trifinity Distribution, remained skeptical about future development. He praised the current mayor for his efforts.

“Just because you have (land) doesn’t mean people will come,” said Merlo, pointing out that much of downtown Waukegan consists of public governmental buildings as opposed to private businesses.

City officials were unavailable after the press conference Tuesday to elaborate on their redevelopment ideas.

But while resurrecting a bedraggled waterfront is a challenge, there are precedents for success, experts said.

Barry Hersh, who teaches about development at New York University, pointed to waterfront efforts with varying visions, including a project that gave over a former steel mill site outside Buffalo, N.Y., to wind turbines and another in Providence, R.I., that replaced a blighted riverfront with a park and walkways.

“If it’s cleaned up … you don’t have to say to a potential developer, ‘Oh, you have to spend $10 million and five years cleaning up the thing,’” Hersh said.

Keys to good waterfront redevelopment include preserving public access and following a broader strategy rather than agreeing to any project that’s proposed, said Tom Murphy, the former mayor of Pittsburgh and now a senior resident fellow at the Urban Land Institute.

Murphy, who pushed ambitious, costly and sometimes controversial projects in the former steel hub crisscrossed by rivers, said city officials need to learn to imagine their waterfronts becoming something entirely different.

“Nobody could believe that anybody would invest in Pittsburgh when we started this process,” he said.

Asked whether a once notoriously polluted waterfront can rehabilitate its reputation to attract development, Hersh said he thinks federal environmental authorities are cautious about proclaiming something clean, though he acknowledged the public might remain wary.

“A former high EPA official (said), ‘They believe us when we say it’s dirty. They don’t believe us when we say it’s clean,’” Hersh said.

Murphy said it’s not impossible to overcome public skepticism about pollution. After all, he noted of Pittsburgh, “Our rivers (used to) catch on fire.”